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TENSION DEVICE FOR SEWING MACHINES. No. 564,557. Patented July 21, 1896.

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J J.B.D-QBYNB. TENSION DEVICE FOR SEWING MACHINES. N0. 564,557

Patented July 21, 1896;

UNITED STATES PATENT OFFICE,

JAMES B. DOBYNE, OF ST. LOUIS, MISSOURI, ASSIGNOR TO THE LANDIS- lVAX THREAD SEWVING MACHINE COMPANY, OF SAME PLACE.

TENSION DEVICE FOR SEWING-MACHINES.

SPECIFICATION forming part of Letters Patent No. 564,557, dated July 21, 1896.

Application filed May 16, 1895. Serial No. 549369. (No model.)

T to whom it may concern.-

Be it known that I, JAMES B. DOBYNE, a citizen of the United States, residing at St. Louis, in the State of Missouri, have invented certain new and useful Improvements in Tension Devices for Sewing-Machines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to a tension-lock attachment and means for regulating the movement or throw of the tension-lever, and has for its object to provide improvements of this character that will greatly facilitate the operation of these parts.

In the drawings, Figure 1 is a front elevation of a machine embodying my improved features; Fig. 2, a broken-away plan; and Fig. 3, a broken-away part elevation and part section on line 3, Fig. 1, looking in the direction indicated by the arrow.

A represents the supporting-base; A, the stationary overhanging arm; A the needlelever; A the needle-bar; A the needle; A the combined needle-cam and fly-wheel; B, the driving-shaft, and B, the take-up lever.

A bracket B is bolted on the shoulder of the overhanging arm. On the outer end of this bracket are supported the corresponding ends of a double-plate tension-spring consisting of the upper member or leaf 0 and the lower member O. The inner end of the spring-supporting bracket is provided with a fulcrum-post a, on which the springs bear at this point, their inner ends extendingbeyond this bearing-point, as shown in Fig. 1. The under spring member is provided with the bowed part a, for the purpose of increasing the resilience thereof and incidentally to conveniently permit of the insertion of the thread a through an aperture a in the upper spring member.

A slide or draw rod D has a vertical position back of the take-up lever and needle-lever. On the upper end of this rod is mounted an open collar a, adj ustably clamped thereon by means of a screw a This collar is provided with a horizontal finger projection at, extending across, Figs. 2 and 3, the top of the inner ends of the springs and bearing thereon at a point in advance of the fulcrum-post a. The pins a prevent the compressing-finger from having a lateral movement. On the lower end of rod D is adjustablymounted a collar Z), having a lug b, Fig. 3, projecting toward the needle-lever. A corresponding lug-b is formed on the needle-lever and is adapted to have an intermittent contact with lug b through the vibratory action of said lever, as will be explained farther along.

It will be noted that the rod D hangs loosely in position, being suspended from the finger projection a, bearing on the tension-spring members, and is so adjusted that the lug on the needle-lever, on the down movement, comes in contact with the lug on rod D and forces the same downward, which has the effect of bending down the inner ends of the tension-spring members and clamping or looking the thread therebetween at the proper time with reference to the movement of the needle and the take-up lever so as to always insure an even pullin for every stitch.

The contact of the lugs on the lower end of rod D and the needle-lever is of but short duration, and is regulated by the adjusting-collars and timed with reference to the movement of the cooperating parts.

hen the pressure of the lug on the needlelever is relaxed, the rod D is raised to its normal position by the tension-spring, the down movement bending it over its fulcrum-post. The tension of the double spring is regulated by a thumb-screw 9 inserted down through the springs and having a threaded engagement in the bracket-support.

The take-up lever B is provided with a pivot-bearing d, and has a friction-roller d mounted on the rear end thereof. To the vibrating needle-lever, just under this end of the take-up lever is secured a lifting-plate 6, having its contacting edge beveled, as at (1 The plate is adjustably secured to the needlelever by a clamping-bolt 61*, inserted through a slot 9 in said lever, so that the contact with the take-up lever may be earlier or later, as the nature of the work-requires. The downward movement of the rear end of the takeup lever is arrested by a stop 9, so that the lifting-plate and take-up lever do not have a continuous contact; but when in the position illustrated in Fig. 1 they are separated by a considerable space, the needle being at about its highest point. As the needle enters the work the lifting-plate is set to come in contact with and raise the rear end of the takeup lever against the action of its spring and causes a corresponding downward movcmen of the front end thereof.

To the rear end of the take-up lever is connected one end of a spring h, the lower end of which is connected With an adj usting-screw 7L, inserted loosely down through a lug 7L2, and has an ad justing-nut 7L threaded on the lower end thereof. This spring returns the lever to its normal position and provides for a tension adjustment with reference to the weight of the thread.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. Ina sewing-machine, the fiat plate tension-spring, the slide-r0d supported on the frame and having an adjustable bearing-pieceengaging said spring, and an adj ustable piece in position for engagement by the needle-le-- ver, all combined substantially as described.

2. The plate-tension spring supported on a bracket on the machine-arm as described, a vertical rod having a collar held thereon by a set-screw, said collar having a finger projection extending across the upper spring at JAMES B. DOBYNE. \Vitnesses:

L. M. FREEMAN, L. B. COUPLAND. 

